1. Field of the Invention
The invention pertains to underground septic system tanks such as a distribution tank, fluid separator tank, and settling tank, that is adapted for burial directly in the soil, which is connected by pipe to other elements of the septic system.
2. Description of the Prior Art
A septic system underground tank is cast with permanent lateral openings or holes for receiving septic system pipe. For various reasons including accessability, water table, and local rules, the tank must be buried at a specific depth, and the pipe must be attached to the tank at a specific depth. This means that the tank has to be ordered with the holes at a specific height between the top and the bottom of the tank. Alternatively, the tank can be purchased without any holes, and holes have to be cut through the side at the construction site. The later choice is time and labor consuming, requires additional on-site tools and carries with it the chance of damaging the tank. An example of a Prior Art tank is described in FIG. 1 below. A septic system underground tank with seal apparatus for it, is disclosed in U.S. Pat. No. 4,663,036 patented May 5, 1987 by Strobl, Jr. et al.
It is one object of the invention to provide a septic system tank that can be buried to a specific depth relative to the earth or to the top or bottom of other tanks in the system while one or more pipes can be connected to the tank at any one of a plurality of different heights between the top and the bottom of the tank. Other objects and advantages of the invention will become apparent to persons skilled in the art from the ensuing description.
A septic system plastic fluid distribution tank adapted for subterranean burial, having a top and a bottom, includes a first vertical outer wall, a plurality of grooved annular circuits molded on the wall of equal diameter, extending in vertical overlapping sequence, the centers of the annular circuits being vertically spaced from one another, formed on the wall so that a hole can be made through the wall at any height of a plurality of heights between the top and the bottom of the wall by removing the portion of the wall that is circumscribed by the circuit at the desired height.
Preferably, at least one circuit of the plurality of grooved circuits is discontinuous at an intersection with another circuit of the plurality of grooved annular circuits.
Preferably the side of the groove that is toward the outer diameter of the circuit slopes at at least two different angles from the outer wall of the tank.
Preferably the opposite sides of at least one groove of the plurality of grooved annular circuits slope asymmetrically in cross section.
A plate, molded with in one piece with the tank is mounted on the bottom of the tank by a living hinge configured for vertical movement of the plate.